There were product-wide modifications on the compressed-air system and the brake system of the UHN in December 2019.
With the use of these product-wide modifications, hydraulic brake systems are no longer installed.
In model 437.421, the modified compressed-air system and brake system have been installed on special request in vehicles with code B89 (Low-pressure brake system) since March 2017.
Since December 2019, only the modified compressed-air system and brake system in combination with code B89 (Low-pressure brake system) have been installed as standard in models 437.421/426/431/436.
In future, code B89 (Low-pressure brake system) will be discontinued in the vehicle data card, but the modified compressed-air system and brake system will still be installed as standard.
In the compressed-air system, a change of 18.3 bar to 10.0 bar occurred in the system pressure.
This has been modified in combination with new components.
Various component parts have been replaced on the control of the service brake.
Further information can be found in the "Introduction to Cross-Country Capable Unimog UHN with Modified Compressed-Air System and Brake System".